President Biden temporarily transferred his power to Vice President Kamala Harris Friday while he underwent a colonoscopy under anesthesia. The procedure was a part of his routine annual physical. The brief transfer of power — one hour and 25 minutes, to be exact — made Harris the first female acting president. She worked from her office in the West Wing during that time. White House press secretary Jen Psaki noted that President George W. Bush also transferred power temporarily for the same procedure in 2002 and 2007. The president signed letters addressed to congressional leadership informing them of the temporary transfer of power. “In accordance with the provisions of section 3 of the Twenty-Fifth Amendment to the United States Constitution, this letter shall constitute my written declaration that I am presently unable to discharge the powers and duties of the office of the president of the United States,” Mr. Biden wrote at 10:10 a.m. “Pursuant to section 3, the vice president shall discharge those powers and duties as acting president until I transmit to you a written declaration that I am able to resume the discharge of those powers and duties.” In the subsequent letters to congressional leadership, Mr. Biden wrote at 11:35 a.m.: “In accordance with the provisions of the Twenty-Fifth Amendment to the United States Constitution, I hereby transmit to you my written declaration that I am able to discharge the powers and duties of the office of the president of the United States and that I am resuming those powers and duties.” The White House said in May that he would undergo his medical checkup at some point this year and that its results would be released to the public but had offered no further updates until Friday. His last physical on record was nearly two years ago in December 2019, when he was a candidate. At the time, Mr. Biden’s doctor said he was a “healthy, vigorous, 77-year-old male, who is fit to successfully execute the duties of the presidency.” The doctor did note he has an irregular heartbeat, called nonvalvular atrial fibrillation. Mr. Biden, the country’s oldest president in history, turns 79 Saturday.